Creep in Precast-Concrete Sandwich Panels Made with Diagonal-Bar Shear Connectors

This is the authors' abstract. We don't add key points for this paper.

This paper aims to investigate and explain the influence of creep of concrete, insulation, and diagonal bars on the behavior of precast-concrete sandwich panels. A theoretical model is developed based on a layered structural modeling of the panel. Each reinforced concrete layer is modeled as an Euler-Bernoulli beam, and the insulation layer is modeled as two-dimensional linear viscoelastic continuum. For the analysis, the panel is divided into a number of regions through its length, and the diagonal bars are introduced via continuity requirements between different regions. Each region along the panel is divided into a number of layers in order to account for cracking, tension-stiffening, and different creep responses of each material point. Creep is accounted for using a convolution integral based on the modified principle of superposition that accounts for the material nonlinearity in tension. From the expansion of the relaxation moduli into a Prony series, an incremental exponential law is obtained, and a step-by-step time analysis was conducted. The results provide insight into the main parameters that control the creep response of composite concrete sandwich panels and provide a basis for the design and analysis of their time-dependent response.